Quick configurable API validations for Express.js

Features

• Simple - Provides a simple and quick way to configure API validations.
• Clean - Unlike other libraries, quick-validate does not require you to write a lot of code for adding simple validations. It uses simple JSON configuration files which do not pollute application code.
• Readable - The validations are much more readable and comprehensible.

Installation

npm install quick-validate --save

Usage

• Create a directory named validations inside root of your project. This is not required but is recommended as a good practice.

• Create 2 files inside the validations directory - apiValidations.json and validationSchema.json

apiValidations.json should specify validations for each endpoint. validationSchema.json should specify type and other constraints about each attribute to be validated.

apivalidations.json

{
  "POST": {
    "/product": {
      "body": {
        "required": ["title", "img_url", "price", "availability_status"],
        "optional": ["description"]
      }
    }
  },
  "PUT": {
    "/product/:product_id": {
      "body": {
        "optional": [
          "title",
          "img_url",
          "price",
          "availability_status",
          "description"
        ]
      }
    }
  },
  "GET": {
    "/products": {
      "query": {
        "required": ["q"]
      }
    }
  },
  "DELETE": {
    "/product/:product_id": {
      "headers": {
        "required": ["admin_token"]
      }
    }
  }
}

As shown in above example, the configuration object structure should be

{
  "httpMethod": {
    "endpoint_path1": {
      "required": ["attr1", "attr2"],
      "optional": ["attr3"]
    },
    "endpoint_path2": {
      "required": ["attr1", "attr2"],
      "optional": ["attr3"]
    }
  }
}

validationSchema.json

{
  "title": {
    "type": "String"
  },
  "img_url": {
    "type": "String"
  },
  "price": {
    "type": "Number"
  },
  "availability_status": {
    "type": "regex",
    "regex": "^(IN_STOCK|OUT_OF_STOCK)$"
  },
  "description": {
    "type": "String"
  },
  "q": {
    "type": "String",
    "minlength": 3,
    "maxlength": "50"
  },
  "admin_token": {
    "type": "String",
    "length": 32
  }
}

• Import and use quick-validate in your app.js

Using ES6 (Recommended)

import * as quickValidate from "quick-validate";
import apiValidations from "./validations/apiValidations.json";
import validationSchema from "./validations/validationSchema.json";
import express from "express";

const app = express();
app.use(express.json());

quickValidate.enableValidations(app, apiValidations, validationSchema, true);

Good ol' way

var quickValidate = require("quick-validate");
var apiValidations = require("./validations/apiValidations.json");
var validationSchema = require("./validations/validationSchema.json");
var express = require("express");

var app = express();
app.use(express.json());

quickValidate.enableValidations(app, apiValidations, validationSchema, true);

The last argument is a boolean which tells quick-validate if extra attributes which are not specified in the validation config for an endpoint, should be removed. This should be usually set to true.

• Intercept validation errors with middleware

app.use(function (err, req, res, next) {
  res.json({
    ok: false,
    error: {
      code: err.code,
      reason: err.message,
    },
  });
});

Schema Properties

Click on property name to see example

name	purpose
type	datatype of attribute
length	length of 'String' type attribute
minlength	min length of 'String' type attribute
maxlength	max length of 'String' type attribute
regex	specifies a pattern to match with
enumVals	specifies a set of enums to match with
missing_err_code	error code to return if missing
invalid_err_code	error code to return if datatype is invalid

Supported 'type'(s)

type	purpose
String	Any string
Number	int, float or any string representing same
boolean	boolean
Array	Any array
Object	Any Object
email	valid email
password	matches strict password policy
enum	matches a set of given values
regex	matches a given regex pattern

Examples

length

{
  "otp": {
    "type": "String",
    "length": 4
  }
}

minlength maxlength

{
  "username": {
    "type": "String",
    "minlength": 5,
    "maxlength": 15
  }
}

regex

{
  "ip": {
    "type": "regex",
    "regex": "^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"
  }
}

enumVals

{
  "availability_status": {
    "type": "enum",
    "enumVals": ["IN_STOCK", "OUT_OF_STOCK"]
  }
}

Putting it all together

validationSchema.json

{
  "username": {
    "type": "String",
    "minlength": 5,
    "maxlength": 15
  },
  "password": {
    "type": "password"
  },
  "email": {
    "type": "email"
  },
  "gender": {
    "type": "enum",
    "enumVals": ["M", "F", "T"]
  },
  "age": {
    "type": "Number"
  },
  "is_married": {
    "type": "boolean"
  },
  "name": {
    "type": "String",
    "minlength": 5,
    "maxlength": 40
  },
  "x-forwarded-for": {
    "type": "regex",
    "regex": "^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"
  }
}

apivalidations.json

{
  "POST": {
    "/user/signup": {
      "body": {
        "required": ["username", "password", "email", "gender", "age", "name"],
        "optional": ["is_married"]
      },
      "headers": {
        "required": ["x-forwarded-for"]
      }
    },
    "/user/login": {
      "body": {
        "required": ["username", "password"]
      }
    }
  }
}